Diesters of dithiophosphoric acids and terpenes



Patented Jan. 5, 1954 DIESTERS F DITHIOPHOSPHORIC ACIDS AND TERPENES Frederick B. Augustine, Jefferson, N. J., assignor to Socony-Vacuum Oil Company, Incorporated,

a corporation of New York No Drawing. Original application October 28, 1947, Serial No. 782,672. Divided and this application January 6, 1949, Serial No. 69,602

8 Claims.

This invention relates to a new process of preparing certain reaction products from diesters of dithiophosp-horic acids and terpenes and to the products so prepared.

Prior to this invention the diesters of dithio phosphoric acid were known and had been added in minor quantities to mineral oil, mainly for the purpose of stabilizing the oil. However, these esters have not been entirely satisfactory for this purpose because of their high acidity, their tendency to corrode metals such as copper, and their effect of causing sludge formation in oils. On the other hand, the neutral triesters of dithiophosphoric acid are relatively difiicult and expensive to prepare.

Accordingly, it is the purpose of this invention to provide a new and expedient process for producing certain new reaction products from esters of dithiophosphoric acid and terpenes, which reaction products are highly useful addition agents for oil.

To this end the present invention comprises the reaction of diesters of dithiophosphoric acid with terpenes, for example, pinene or dipentene.

Diesters of dithiophosphoric acid can be prepared in a number of ways, but the most generally used method is that of reacting a compound containing an hydroxy group, for example, an alcohol or a phenol, with phorphorus pentasulfide. This reaction proceeds essentially as follows:

As organic hydroxy compounds for reaction with the phosphorus pentasulfide, normal straight chain alcohols, branched chain alcohols, hydroxy aryl compounds, such as phenol and naphthol, substituted aryl hydroxy compounds, such as diamyl phenol or any other other hydroxy organic material in which the hydroxy group will react with the phosphorus pentasulfide may be used.

In a similar manner, any organic material containing a mercaptan radical may be reacted to produce a thioester corresponding to the oxygen esters described above.

It has now been discovered that the products, the manufacture of which has been described above, can be expediently converted into far less acid, or completely nonacid, products of a far more useful nature, by reacting them with a terpene or a mixture of terpenes.

A variety of terpenes react with secondary esters of dithiophosphoric acid in the manner described generally above. Specifically investigated were pinene, dipentene, allo-ocimene and terpineol, representing, respectively, bipyclic,

monocyclic, acyclic and hydroxy terpenes or terpene derivatives. Each of these evidenced positive reaction by evolution of heat and reduction of acidity. However, pinene is the preferred terpene; it yielded neutral products which passed copper corrosion and heat stability tests. The other terpenes did not react to completion, and sufiicient residual acidity remained to fail the products in copper corrosion and heat stability tests, even following extended reaction time. Such terpenes may be of utility, however, for example, as a replacement for part of the pinene in some of its reactions.

The temperature necessary to effect the reaction is generally about C. to about 200 C. and the time required is generally less than five hours.

Example I Four molecular proportions of refined fusel oil and one molecular proportion of phosphorus pentasulfide were mixed and, after the initial reaction had subsided, heated at 90 C. for 2 hours. The neutralization number of the product, essentially diamyldithiophosphoric acid, was 185, expressed as milligrams of potassium hydroxide equivalent to 1 gram of sample.

To 50 grams of this acid was added 38 grams of pinene with immediate evolution of heat. Reaction at 150 C. for 2.5 hours yielded a product of neutralization number 13, containing 6.13% phosphorus and 16.6% sulfur.

Example I] One molecular proportion of phosphorus pentasulfide was carefully added to 4.0 molecular proportions of ethyl alcohol. After the vigorous reaction had subsided, the temperature was maintained at 80 C. for 2 hours. The neutralization number of the product, essentially diethyldithiophosphoric acid, was 263.

The spontaneous reaction upon mixing 186 grams of this acid with 272 grams of pinene carried the temperature to C. After 3 hours reaction at 0., the product had a neutralization number of 2. It was washed with dilute alkali and freed of excess pinene by vacuum topping. The residue contained 9.31% phosphorus, 19.6% sulfur and had a neutralization number of 1.5.

Example III Diphenyldithiophosphoric acid was prepared by heating together 222 grams (1 mol) of phosphorus pentasulfide and 376 grams (4 mols) of phenol. Reaction proceeded rapidly at ISO-150 C. and after one-half hour at ISO- C. no solid remained. The yield of black residue,

which solidified at about 80 C. and had a neutralizationnumber of 208, was 558 grams.

To 282 grams of this acid was added 2'72 grams of pinene with immediate evolution of heat. There was no change in combined weight even after 3 hours reaction at 150 C. Excess pinene was removed by distillation under vacuum, and the yield of a dark red, clear liquid residue was 416 grams. It contained 14.9% sulfur, 7.22% phosphorus and had a neutralizationrnumber of 1.

Example IV Example V An acid essentially bis (2-ethylhexyl) dithiophosphoric acid was prepared by reacting 624 The above results show the improvement obtained by reacting a dithiophosphoric acid with a terpene and particularly with pinene.

The copper strip corrosion test consists in placing a polished copper strip about 2" 1 bent into a V shape, in a 100 ml. beaker so that the fiat surface of the strip does not touch the bottom or sides of the beaker. 50 ml. of oil are then placed in the beaker so as to completely cover the copper strip. The beaker is then placed in an electric oven for the specified length 01' time at a specified temperature. Thereafter the copper strip is; removed and washed with petroleum ether and examined for corrosion. To pass this test, the strip must show no more than negligible. discoloration after 3 hours and no more than moderate discoloration after 24 hours.

The heat stability test consists in maintaining .an oil blend of the additive at 150 C. and ob-' serving. for the appearance of sludge.

BUBBLE TEST l on+o.25% product of'Exomple r+o.05% ncu- 1 grams of 2-ethylhexanol and 266 grams of phosi k jg g 4 19 phorus pentasulfide at 150 C. for several hours. 3 W m 2 It had a neutralization number of 130. i 5 Pm 5 v A. solution of '79 grams of this acid and 136 (fai -0105;, $3.32., 2.13;: v 1 4% grams of dipentene was heated at 140 C. for 2 ..1 i hours neutmhzatgm nuntber' of the 1:: The above results show. the effectiveness of acted solutionwas 8. xcess erpene was 1 these m at arms in preventing bearing weight moved by topping to.150 C. pot temperature at loss The yield of viscous resl'du'ei'nemmhz A bubble test. is conducted for the purpose of anon number was 93 grams measuring the corrosion of hard metal bearings Example VI by an oil including the new compounds. This test is conducted in a ZOO-X25 mm. test tube in Diphenyldithiophosphoric acid was prepared j as berof19'7. To 94mm 91 grams of a erati n:its dipentene with the evolution ofheat" The Soludown to about 1 mm inside diameter to a out tion was heatedat 150 C. for 3 hours. The neu- 30 mm at e d to f air to i g tralization number of the reacted solution was tom Of'the tst a 33i Yssemb 7 is n81 d Excess terpene by pping at 1 75 c for 22 hours and a r blown through a}; 1 The meld Vlscous resldue the inlet tube and into the bottom of the oil neutralization number 28.5, was 128 grams. bath at a rate of 2 liters per hour during that Emmple VII time. The test piece is then removed and T .94, rams f th p y d thi p phor c Welghed e -W an-X1955 Welght' Whwh or a loeimen Af r reac. ion a 1 5- C- Y a Y for 5 hours, they solution had a neutrauzatiqn Pennsy vania neutral and res1duumstockssepnumber 245' The prpduct was dissolved in arately refined by means of chlorerr and then benzene and treated with dilute sodium hydroxan motol -P ide. The benzene layer was washed with Water, Speclfic gmwty of 7 h of filtered and freed of solvent byv topping to 150 C. and a Saybolt Unlvelsal llscoslty of 318 at 2 mm, The yield of viscous residue, neusefionds t- 0 9 tralization number 8.5, was 126 grams. Asample of this oil wi hout additive was tested Copper strip corrosion test Heat stability Addams i S fE an 24h i s Af'E io oil, 00 6. 6 go oi] percent percent UnreactedacidoiExampleI. 0.6 Failed... Failed... 0.6 Heavy sludge. ProductofEx.I.. 1.0 PasserL. Passed.. 1.0 Nosludge. Product of Ex. II 1.0' Product of Ex. n1; 1.o .0 Do. Product of Ex. IV 1,0 0 Slude'e. Product of Ex.V 1.0 .0 Do. Product of Ex. VI; l. 0 Product of Ex. VII. 1. 0

a ,3 concurrently with samples containing additive in each of the above runs.

LAUSON ENGINE STABILITY TEST 1 After 24 hours.

The above results show the effectiveness of these materials in preventing the deterioration of motor oils in engines.

Lauson oxidation stability tests are conducted in a Lauson single cylinder, four cycle, liquid cooled gasoline engine with jet lubrication. This engine uses gallon of oil, the oil temperature under operating conditions is 280 F., jacket temperature 212 at, speed 1815 a. P. throttle setting, open, air-fuel ratio, 13:1, length of the test, 36 hours. No oil is added during the test. The fuel used is 100% straight run gasoline plus 2.5 cc. of tetraethyl lead. The oil used in this test was a solvent-refined S. A. grade motor oil having a kinematic viscosity of 5.75 at 210 F., and a flash point of 415 F. The neutralization number (milligrams of potassium hydroxide required to neutralize one gram of oil) and the viscosity were determined at the end of the test as an indication of the deterioration that had taken place in the oil.

This application is a division of application Serial Number 782,672, filed October 28, 19%7, now Patent No. 2,561,773, issued on July 24, 1951.

What is claimed is:

1. A process of preparing reaction products that comprises reacting about one mol of a saturated diester of dithiophosphoric acid with about one mol of a terpene, at temperatures between about 100 C. to about 200 C.

2. A process of preparing reaction products that comprises reacting about one mol of a saturated diester oi dithiophosphoric acid with about one mol of pinene, at temperatures between about C. to about 200 C.

3. A process of preparing reaction products that comprises reacting about one mol of a saturated diester of dithiophosphoric acid with about one mol of dipentene, at temperatures between about 100 C. to about 200 C.

4. A process of preparing reaction products that comprises reacting about one mol of a saturated diester of dithiophosphoric acid with about one mol of a terpene by heating the reactants together at temperatures between about 100 C. to about 200 C.

5. A process of preparing reaction products that comprises reacting about one mol of a saturated diester of dithiophosphoric acid with about one mol of a terpene by heating the reactants together at temperatures between about 100 C. to about 200 C. for at least about two hours.

6. As a new composition of matter a reaction product obtained from the reaction involving about one mol of a saturated diester of dithiophosphoric acid with about one mol of a terpene, at temperatures between about 100 C. to about 200 C.

7. As a new composition of matter a reaction product obtained from the reaction involving about one mol of a saturated diester of dithiophosphoric acid with about one mol of pinene, at temperatures between about 100 C. to about 200 C.

8. As a new composition of matter a reaction product obtained from the reaction involving about one mol of a saturated diester of dithiophosphoric acid with about one mol of dipentene, at temperatures between about 100 C. to about 200 C.

FREDERICK B. AUGUSTINE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,379,312 May June 26, 1945 2,381,377 Angel et a1. Aug. 7, 1945 2,455,668 Fuller et a1. Dec. 7, 1948 

1. A PROCESS OF PREPARING REACTION PRODUCTS THAT COMPRISES REACTING ABOUT ONE MOL OF A SATURATED DIESTER OF DITHIOPHOSPHORIC ACID WITH ABOUT ONE MOL OF A TERPENE, AT TEMPERATURES BETWEEN ABOUT 100* C. TO ABOUT 200* C. 